Hierarchical Black Hole Mergers in AGN Disks: Tracing Massive Black Hole Growth Across Cosmic Time
This work presents a semi-analytical model showing how dense gas disks around Active Galactic Nuclei (AGN) can catalyze repeated mergers of stellar-mass black holes, potentially explaining high-mass binary black hole (BBH) mergers. The model incorporates gas capture, migration, and three-body interactions to predict hierarchical mergers that can produce massive remnants and constrain the growth history of supermassive black holes.